This invention relates to a process for making dicarboxylic acids in which a cycloalkene is ozonized to produce an ozonide, the ozonide is converted to an acid aldehyde in the presence of heat and a base, and the acid aldehyde is oxidized to produce the desired dicarboxylic acid.
It is known that ozonolysis of cyclododecene is a way of making dodecanedioic acid. See, for example, U.S. Pat. 3,280,183. The use of ozone as an oxidant and as an initiator for autoxidation also is known. (See Philip S. Bailey, xe2x80x9cOzonation in Organic Chemistryxe2x80x9d, pp. 302-307. Academic Press, New York, 1982.)
It is known in the art that a cycloalkene can be converted to a dicarboxylic acid using three separate, sequential reaction steps, conducted under different conditions. The first step, ozonolysis, involves contacting the cycloalkene with ozone at a low temperature, typically 20xc2x0 C. or less. The ozonide so formed is then re-arranged with or without a base catalyst at a higher temperature, typically 80 to 100xc2x0 C., to form an acid aldehyde. The acid aldehyde is then air oxidized at 80 to 100xc2x0 C. to form the desired dicarboxylic acid product.
The present invention is a process for making an alkanedioc acid, in which the alkane moiety contains 6 to 12 carbon atoms, comprising, forming a reaction mixture comprising a cycloalkene having the same number of carbon atoms as the alkane moiety of the alkanedioc acid, a C1 to C9 organic acid solvent, and a base catalyst, which is a metal salt of the organic acid, and contacting the mixture simultaneously with oxygen and ozone at a temperature between about 40 to about 60 degrees C. to obtain a product mixture comprising the alkanedioic acid.